Some Covid-19 Epidemiological Data and Personal Reflections

Because I am teaching Environmental Health this semester (for public health undergraduate majors), the class has been tracking the coronavirus (COVID-19) outbreak all semester. Nothing like a case study in real time. I thought I would share some of the epidemiological data that we have been watching. As scary as it can be at times, as a scientist, I value evidence.

When we first started paying attention in mid January, the only cases of coronavirus (not yet called COVID-19) were in China. The map from John Hopkins University showing the extent of the outbreak looks very different now than it did back in January. It looked very different a week ago.

From the JHU CORVID tracking dashboard

The confirmed cases from China are represented in the graph below as they emerged over time (the orange data points/line).

Actual Cases of Corvid (China in orange, elsewhere in yellow, recovered in green). Data from JHU

The green data points represent the number of people who have recovered to date. Fortunately, after the initial lag, that graph is going up now. Reports from the Wuhan region of China signal that they are through the worst of this about three months after the initial cases of the disease (although there were probably some earlier cases). You can see this in the flattening of the orange curve.

According to the data visualized by John Hopkins University (collected from a variety of global sources including the World Health Organization), as of March 16th at 6:33 pm, there were 181,377 confirmed cases globally (this is almost 12,000 more than at 11:30 last night). There are currently 7133 official deaths reports (vs. 6513 at 11:30 last night). This is the "Buthcher's Bill" to use a reference from And The Band Played On, the movie about the early days of HIV/AIDS.

The yellow data points in the graph represent the cases outside of China (i.e. the rest of the world). I call your attention to the relative rate of increase in these cases versus the trends from China (the sharp slope of the yellow line compared to the orange one). There are likely many cases that were missed on the front end of this outbreak and many more that haven't been confirmed in parts of the world, including the U.S., due to a shortage of tests.

In the U.S., presumptive cases are documented through tests done locally; confirmed or definitive cases are confirmed through the CDC. So a) there is a lag, and b) many people who have symptoms are not being tested, so - at least for the U.S. - our numbers significantly underestimate the extent of the outbreak.

The image below (also from the JHU source) shows the number of new cases confirmed per day (in red) and recovered (in green). The spike on February 13th was due to a revised case definition in China.

Daily record of new cases of COVID-19 (red) or recovered (green). Data from JHU.

Note that the biggest one day jump so far occurred today, March 16th. The recent spikes are simply massive jumps in new cases - not a redefinition of the disease. In the past 24 hours, 368 people died in Italy alone.

Now the less objective observation: Having taught the history of disease in the past, including how societies respond and the impacts of inequality, it isn't surprising to see some of the behaviors we are all witnessing. It was the same in the time of the bubonic plague outbreaks and when the new disease we now know as HIV/AIDS first emerged. Some people rise to the occasion and show empathetic leadership, generosity and kindness. Others are greedy, self-centered, fearful, willing to profit from the hard luck of others, delusional (the deniers) or simply just jerks.